The present invention relates to a method for manufacturing a semiconductor device and an IC chip which can meet demand of small-sizing and thinning. More particularly, the invention relates to a method for manufacturing a chip-scale package and an IC chip, which can manufacture a thin chip-scale package by back grinding in a state where an active face of an IC wafer is protected.
In recent years, with the advent of single-unit video camera-recorder, portable telephone, and the like, a portable device on which a small-sized package having almost the same size as that of a bare chip, what is called, a CSP (Chip-Scale Package) has appeared. Recently, the CSP which is formed by coating a protective resin on an IC chip is being developed rapidly and it realizes a small, thin, and high-density semiconductor device.
Japanese Patent Application Laid-Open No. 10-79362 discloses a technique regarding a method for manufacturing a chip-scale package to satisfy the demand of small-sizing and thinning.
The technique will be described briefly hereinbelow.
A semiconductor device is manufactured by, generally, a semiconductor device forming process, a bump forming process, a resin sealing process, a projected electrode exposing process, a dicing process, and the like.
In the publication, a method for manufacturing a semiconductor device is disclosed as the nineteenth embodiment.
FIGS. 16A to 16C show the method for manufacturing a semiconductor device disclosed as the nineteenth embodiment.
In FIG. 16A, before the resin sealing process, a relatively wide groove 105 for dicing is formed in a part in a substrate 116 (wafer on which a number of semiconductor devices are formed) to be diced in a post process. The groove 105 is formed so that a part of the substrate 116 remains on the bottom of the groove 105. The width of the groove 105 is set so as to be wider than at least the width of a dicer 129.
In the resin sealing process, a resin layer 130 is formed on the substrate 116, the groove 105 is filled with a sealing resin to form a resin layer 106. After completion of the resin sealing process, a dicing process is performed. In the process, as shown in FIG. 16B, the substrate 116 is diced into pieces by using the dicer 129 in a dicing position X in the groove 105 filled with the resin layer 106. FIG. 16C shows the diced state of the substrate 116.
In the dicing process, the dicing process is performed in the groove 105 in which the resin layer 106 is formed, and the resin layer 106 becomes thicker than the other resin layer 130 on the active face. Consequently, the mechanical strength can be enhanced.
Since the resin layer 106 is more flexible than the substrate 116, a stress applied on the substrate 116 can be absorbed. In the dicing process, therefore, it can prevent occurrence of cracks in the substrate 116 and the resin layer 130. Also, the manufacturing yield of the semiconductor device can be increased.
At the time point of completion of the dicing process, the resin layer 106 is exposed on a side face of the substrate 116. In a part corresponding to the bottom of the groove 105, the diced face of the substrate 116 is exposed. In the event of carrying a semiconductor device, exposed parts in the resin layer 106 are held by using a handling device.
U.S. Pat. No. 5,888,883 discloses a method of dividing a wafer and a method of manufacturing a semiconductor device to satisfy the demand of small-sizing and thinning.
According to this method, the groove, the depth of which is deeper than a thickness of a finished chip is formed on one surface of a wafer along dicing line. After the wafer is fixed on a table of a grinding device by a PSA tape, the other surface opposing to the PSA tape of the wafer is grinding to reach the grooves. Thereby, the wafer is easily divided into the individual chips.
However, these above-mentioned methods for manufacturing the semiconductor device have a problem that the exposed parts are often damaged by the handling device, since the diced face and the corners of the substrate are exposed.
Japanese Patent Application Laid-Open No. 10-79362 also discloses, as the twenty-first embodiment, a method for manufacturing a semiconductor device, which prevents a damage at the time of handling by forming a resin layer on the whole side faces of the diced substrate 116 so as to cover the exposed parts.
FIGS. 17A to 17D show the method for manufacturing the semiconductor device according to the twenty-first embodiment.
In the embodiment, as shown in FIGS. 17A to 17D, before the resin sealing process, a first dicing process is performed to dice the substrate 116 into semiconductor devices 112. Bumps 120 and electric circuits are formed on each of the semiconductor devices 112.
After completion of the first dicing process, the resin sealing process is performed. In the resin sealing process, as shown in FIG. 17A, the semiconductor devices 112 once diced are aligned and mounted on a film member 113 as a base material in a state where a gap 114 is formed between the neighboring semiconductor devices 112.
At this time, the semiconductor device 112 is adhered to the film member 113 by using an adhesive.
As described above, after the semiconductor devices 112 are mounted on the film member 113, a resin compression molding process is carried out, and the resin layer 130 is formed on the surface of the semiconductor devices 112. The resin layer 106 is formed in the gap 114.
Subsequently, a projected electrode exposing process of exposing at least the tip of each of the bumps 120 from the resin layer 130 is performed.
FIG. 17B shows a state where the processes are finished.
Subsequently, in a second dicing process, the slicing process is performed in a position between the neighboring semiconductor devices 112, that is, in the position where the resin layer 106 is formed. The resin layer 106 is sliced together with the film member 113 into, as shown in FIG. 17C, the semiconductor devices 112 on which the resin layer 130 is formed. Subsequently, as shown in FIG. 17D, the film member 113 is removed.
As described above, since the side faces and corners of the diced semiconductor devices 112 are covered with a resin, the resin parts can be held by the handling device. Consequently, the semiconductor device 112 can be prevented from being damaged.
The above-described method for manufacturing the semiconductor device has, however, the following problems.
Specifically, in the twenty first embodiment, the substrate is preliminarily sliced into semiconductor devices and the semiconductor devices are aligned at predetermined intervals and adhered to the film member. The work is therefore troublesome and the productivity is extremely low.
In order to serve the demand of a thinner semiconductor device in the market, it can be considered that a thinner IC wafer is used from the beginning. When the thinner IC wafer is processed by the above-described manufacturing method, however, the following problem occurs.
In the manufacturing process, for example, when a very small crack occurs at the time of grinding the IC wafer, the crack may progress during formation of bumps in the bump forming process. The progress of the crack causes many fractures in the wafer and severely deteriorates the manufacturing yield.
It is an object of the invention to provide a method for manufacturing a chip-scale package and an IC chip, which facilitate handling at the time of manufacturing a semiconductor device with satisfying the demands of small-sizing and thinning. It is an another object of the invention to provide a method for manufacturing a cheap chip-scale package and an IC chip with high productivity by preventing occurrence of fractures in a chip.
According to one aspect of the present invention, in order to achieve the object, there is provided a method for manufacturing a chip-scale package, comprising: a semiconductor device forming step of forming a plurality of pad in predetermined positions on an active face of the IC wafer; an electrode forming step of forming a projected electrode in a pad formed on an active face of an IC wafer; a groove forming step of forming a groove in the active face of the IC wafer along a line that the IC wafer is divided into individual pieces; a protective resin applying step of applying a protective resin on the active face of the IC wafer including the groove; an adhesive member applying step of applying an adhesive member on the active face on which the protective resin is applied; a grinding step of grinding an inactive face of the IC wafer which is fixed by the adhesive member until the groove is reached to the inactive face of the IC wafer; an adhesive member removing step of removing the adhesive member applied to the active face; and a separating step of applying an adhesive member to the ground face of the IC wafer, which has been ground in the grinding step, dicing the protective resin along the lines into chip-scale packages in a state where the IC wafer is fixed by the adhesive member and, after that, removing the adhesive member applied to the ground face.
According to another aspect of the present invention, in order to achieve the object, there is provided a method for manufacturing an IC chip, comprising: a semiconductor device forming step of forming a plurality of a pad in a predetermined position on an active face of an IC wafer; an electrode forming step of forming a solder layer on the pad, applying a flux on the active face of the IC wafer and the solder layer, rounding the solder layer applied with the flux by a reflow; a groove forming step of forming a groove on the active face of the IC wafer along a line that the IC wafer is divided into individual IC chips; an adhesive member applying step of applying an adhesive member on the active face; a grinding step of grinding an inactive face of the IC wafer which is fixed by the adhesive member until the groove is reached to the inactive face of the IC wafer; a connecting step of connecting the individual IC chips each other not to be separated by applying an adhesive member on the active face; an adhesive member removing step of removing the adhesive member from the active face; an IC wafer cleaning step of flushing the flux from the active face; and a picking up step of picking the IC chip up from the adhesive member which connects the IC chips each other.
According to another aspect of the present invention, in order to achieve the object, there is provided a method for manufacturing an IC chip, comprising: a semiconductor device forming step of forming a plurality of pads in predetermined positions on an active face of an IC wafer;
an electrode forming step of forming a projected electrode on the pad; a protective layer forming step of applying a photoresist on the active face of the IC wafer and on a gold bump; and a groove forming step of forming a groove on the active face of the IC wafer along a line that the IC wafer is divided into individual pieces: an adhesive member applying step of applying an adhesive member on the active face on which the protective resin is applied; a grinding step of grinding an inactive face of the IC wafer which is fixed by the adhesive member until the groove is reached to the inactive face of the IC wafer; a connecting step of connecting the individual IC chips each other not to be separated by applying an adhesive member on the active face;
an adhesive member removing step of removing the adhesive member applied to the active face; a protective layer removing step of removing the protective layer; and
a picking up step of picking the IC chip up from the adhesive member which connects the IC chips each other.
The projected electrode may be either a solder bump or a gold bump.
Preferably, the protective resin is applied so that the projected electrode is exposed in the protective resin applying step. The protective resin is applied so as to cover the projected electrode in the protective resin applying step. The projected electrode may be exposed after an adhesive member is applied to the ground face of the IC wafer. In this case, the protective resin surface may be subjected to an ashing process to expose the projected electrode.
In the groove forming step of forming a groove in the IC wafer, an adhesive member is applied to an inactive face in advance and, after that, the adhesive member may be removed.
The sequence of each process can be replaced. For example, the groove forming process can be provided before the protective layer forming process. An adhesive member applied to the active face can be removed, after applying an adhesive member to the ground face of the IC wafer.